Internal combustion engine



June 30, 1942. H. SCHMIDT INTERNAL COMBUSTION ENGINE Filed Ndv. 4, 1940 Patented June 30, 1942 UNHTED STATEg i ATENT OFFIQE INTERNAL COMBUSTION ENGINE Henry Schmidt, Detroit, Mich. Application November 4, 1940, SerialNo. 364,201

7 Claims.

This invention relates generally to motor vehicle engines and more particularly to mechanism for increasing the torque on the crank shaft.

One of the objects of the present invention is to provide in an internalcombustion engine a new and improved connecting mechanism for a piston and crankshaft which functions to increase the torque of the crankshaft without increasing the piston stroke.

Another object of the invention is to provide anew and improved piston and'crankshaft connecting mechanism which increases the torque on the crankshaft at the most effective point of rotation of the shaft or for only a portion of the rotation of the shaft.

A further object of the invention is to provide mechanism of the above mentioned character in which the torque increasing mechanism is ineffective on all but the firing stroke of the piston.

Other objects of the invention will become apparent from the following detailed description taken in connection with the accompanying drawing in which:

Figure 1 is a cross sectional view of an internal combustion engine embodying features of the present invention;

Fig. 2 is a sectional view of the engine, taken along the line and in the direction of the arrows 22 in Fig. 1;

Fig. 3 is a View showing certain structural details, taken along the line 33 of Fig. 1;

Fig. 4 is a view partially diagrammatical of an engine including my improved piston and crankshaft connecting mechanism; and

Figs. 5, 6 and '7 are views similar to Fig. 4 but showing the parts in different positions they will assume during operation of the engine.

Referring to the drawing by characters of reference, the internal combustion engine shown includes a crank case ill and a cylinder block H on which a head 12 is rigidly mounted. The engine block 1! includes the usual cylinders I3, of which only one is shown, and in the cylinder is a reciprocal piston it. Above the piston I4 the block H and head I2 cooperate to provide a firing chamber l5 into which the lower end of a spark plug [6 projects, admission of fuel to the chamber !5 being controlled by the usual intake valve H which is actuated by a cam l8 on the cam shaft 20. Immediately below the cylinder l3 there is a crankshaft 2| having a crank 22 which is usually counterbalanced by weights 23, the

arm during operation of the engine.

crank shaft 2| driving the cam shaft 20 through a chain drive 24.

A connecting rod is pivotally connected at one end thereof to the piston M, the other end of the rod being connected by my torque increasing and connecting mechanism to the crank 22, the torque increasing mechanism being designated generally by the numeral 26. The mechanism 26 includes a lever or arm 21 which within the crankcase I'll is pivoted by a pin 28 to and between horizontally spaced lugs 29 formed in. tegral with a side wall of the crankcase l0. Adjacent its free end, the arm 21 is provided with a hook-like upturned end portion 30 where the arm 2'! is pivotally connected by a pin 3| to a depending lug 32 which is integral with a lever 33. The lever 33 extends longitudinally of and above the arm 21 and an end portion of the lever rests or seats against an upper abutment surface 35 of the arm but moves away from the Adjacent its other end, the lever 33 is pivotally connected by a pin 34 to the lower end of the piston rod 25. Yieldable means, preferably a helical coil spring 36 under tension, is provided for holding the lever 33 to the arm- 21, and, when the arm is so held, the lever 33 pivots about the axis of the pin 28 as a fulcrum. A laterally extending pin 3'? in the lever lug 32 engages the hooked end 38. of the arm 2! to limit movement of the lever 33 relative to the arm 21.

The lever 33 is provided with a movable fulcrum, preferably a roller 38, pinned to an extension or upwardly extending arm 39 which is integral with and disposed intermediate the ends of the lever 33. In operation, the roller 38 rolls on a second roller 40, which serves as a reaction member therefor, thus changing the fulcrum of the lever 33, the roller 40 being mounted on a shaft G! which is supported by a pair of spaced lugs 22, integral with and depending from the top crankcase wall. On the opposite side of the fulcrum 38 from the spring 35, a connecting member 44 is provided on the lever 33 to slide reciprocally therealong and connects the lever to the crank 22, the connecting member 44 being pivotally connected to the crank by a pin 45. In the upper surface of the lever 33, a recess d6 provides clearance between the lever and the roller 40.

Operation In Figure 1, when the piston I4 is forced downwardly due to explosion of the fuel charge in chamber l 5, the force is transmitted through the connecting member 44 to the crank pin 45 to rotate the crank 22 clockwise, during which rotation the connecting member 44 slides along the lever 33 to the right. Due to the resistance of the crank 22 to rotate, the lever 33 is caused to pivot counter-clockwise about its pivot pin 3|, which brings the lever fulcrum or roller 38 into engagement with the roller 4!), this engagement taking place preferably when the most effective force of the exploding fuel charge is acting on the piston 14, or when the parts are substantially in the positions shown in Figure 4. In the positions of the parts shown in Figure 4, it will be seen, as illustrated by the vertical dot-and-dash lines, that the distance from the axis of pin 34 to the axis of the crank pin 45 is substantially equal to the distance from the axis of the crank pin 45 to the point of contact of roller 38 with the roller 40 and so at this stage of operation, no lever advantage is obtained. However, as the piston continues downwardly, Figures 5 and 6, it will be seen that the lever arm or distance between the axes of pins 34 and 45 increases while the distance from the aXis of pin 45 to the contact point of rollers 38 and 40 decreases as the roller 38 moves around and downwardly, thus in effect increasing the torque on the crank 22. It will be understood that this increase in torque on the crank 22 is only effective during the explosion stroke of the piston. Thus it Will be seen that as the engine operates, the connecting member 44 will reciprocate on the lever 33 and that the fulcrum of the lever will change as the roller 38 rolls around the other roller 40, thus changing the effective length of the crank arm and con sequently correspondingly changing the torque. When the piston I4 is moved upwardly on either the exhaust or compression strokes of the engine, the lever 33 is held to the arm 2'! and swings upwardly or clockwise, Figure 7, about the arm pivot 28 as a fulcrum. This occurs because on the upstroke of the piston there is no resistance force of the crank 22 to thrust the lever 33 upwardly to engage the roller 31 carried thereby with the roller 40. Also, the torque on the crank 22 is not effective on the fuel intake stroke of the piston 14 because the piston is pulled down by the crank 22 and thus there is no force to move lever 33 or its roller 31 into engagement with the roller 40. the explosion or firing stroke of the piston [4 that there is an opposing force of the crank to thrust the lever fulcrum or roller 37 into engagement with the roller 4!! and consequently it is only during this stroke that the torque on the crank 22 is increased.

While I have shown and described my invention in detail, it is to be understood that the same is to be limited only by the appended claims for many changes may be made without departing from the spirit and scope of my invention.

What I claim is:

1. In an internal combustion engine having a piston and a crank, mechanism for operatively connecting the piston and the crank comprising, a lever member pivotally connected to the piston, a reaction member having a reaction surface varying in its distance from said pivotal connection. and a contact portion on said lever engaging and travelling along said reaction surface during operation whereby to provide a movable fulcrum therebetween during operation, means for operatively connecting said lever member to the crank, and devices connected to said lever and responsive solely to an explosion stroke.

Therefore, it is only during of said engine for bringing said contact portion into engagement with said reaction surface and operative during other strokes of said engine to separate the same whereby to increase said distance and consequently to increase the torque on said crank during the explosion stroke only.

2. In an internal combustion engine having a piston and a crank, mechanism for operatively connecting the piston and the crank comprising, a lever pivotally connected to the piston, a reaction member having a reaction surface varying in its distance from said pivotal connection, and a contact portion on said lever engaging and travelling along said reaction surface during operation whereby to provide a movable fulcrum therebetween during operation, a member carried by and reciprocal along said lever for connecting said lever to the crank, a stationary mounting, and a movable connection attached between said mounting and said lever and yieldable in one direction between said lever and said mounting and engageable in another direction in response solely to an explosion stroke of said engine for bringing said contact portion into engagement with said reaction surface and operative during other strokes of said engine to separate the same whereby to increase said distance and consequently to increase the torque on said crank during the explosion stroke only.

3. In an internal combustion engine having a piston and a crank, mechanism operatively connecting the piston and the crank comprising, a lever member pivotally connected to the piston, a reaction member having a roller path disposed at a variable distance from said pivotal connection, a roller carried by said lever member to engage and roll upon said roller path of said reaction member as a movable fulcrum, a connecting member slidable on and along said lever and connecting said lever to the crank, and devices connected to said lever and responsive solely to an explosion stroke of said engine for bringing said roller into engagement with said roller path and operative during other strokes of said engine to separate the same whereby to increase said distance and consequently to increase the torque on said crank during the explosion stroke only.

4. In an internal combustion engine having a piston and a crank, mechanism for operatively connecting the piston and the crank comprising, a lever having a movable fulcrum and pivotally connected to the piston, a connecting member slidable on and along said lever and connecting the lever to the crank, a pivoted arm disposed in abutting relationship with said lever, and yieldable means connecting said lever and said arm and releasably holding said lever and said arm in said abutting relationship during a part only of the working cycle of the engine.

5. In an internal combustion engine having a piston and a crank, mechanism for operatively connecting the piston and the crank comprising, a pivoted arm having an abutment surface, a lever having a movable fulcrum and seating on said abutment surface, said lever being pivotally connected to the piston, yieldable means acting to hold said lever in engagement with the abutment surface of said arm, said lever being movable about its movable fulcrum relative to said arm, cooperable means on said lever and on said arm to limit movement of said lever relative to said arm, anda connecting member slidable along said lever and connecting the lever to the crank.

6. In an internal combustion engine having a piston and a crank, mechanism for operatively connecting the piston and the crank comprising, a roller, a lever member pivotally connected to the piston, a second roller carried by said lever to engage and roll on said first-named roller as a movable fulcrum of said lever, yieldable means acting on said lever member on one side of said fulcrum and acting to pivot said lever member in one direction, and a connecting member slidable along said lever member on the other side of the fulcrum from said yieldable means and connecting said lever member to the crank.

7. In an internal combustion engine having a piston and a crank, mechanism for operatively connecting the piston and the crank for increasing the torque comprising, a lever member having a movable fulcrum intermediate its ends, spring means acting on said lever member on one side of said fulcrum and operable to pivot said lever member in one direction, and a connecting member slidable along said lever member on the opposite side of the fulcrum from said spring means and connecting said lever member to the crank.

HENRY SCHMIDT. 

